The R34 GT-R is a great car and every details were optimized by Nissan including the battery : it’s small and lightweight : only 6.5kg ! Overall dimensions are (LxWxH) 186x126x168mm.

The downsize is the battery life : small. And at some point you will be looking for a replacement battery. Then you will discover quickly that your battery is unique to your car : yes, that battery was made specifically for the R34 GT-R and it’s only available in Japan.

You need to know that the space for a new battery is limited and the battery has japanese terminals (JIS). I worked it out for hours and you are basically down with two options beside ordering an OEM battery :

change the wire connectors to standard connectors and you can fit a battery like the Bosch S4 001(207x175x175) : it’s a little bigger than the original battery but will fit easily and it’s more powerfull and it will last longer. Beware that to change wire connectors special tools will be required …. it’s not advised to cut wires because they’re short

get a battery with JIS terminals. Unfortunately the standard height of japenese batteries is little too big for the wires : 22cm versus 16cm for the original battery. You will struggle to tighten and to stretch the positive wire on the battery. I have never seen such a battery fitted either by myself or on google. The Bosch S4 018 is that kind of battery. It will last longer BUT it isn’t more powerfull …

I said there were two options. That was until I discover some terminal adapters from JIS terminals to standard terminals ! These adapters allow you to keep the actual JIS terminals and a battery with standard terminals can be plugged in.

Strangely Nissan anticipated a larger battery could be fitted : holes for a larger battery are already done ! You will need to make a battery retainer as the original one is too small (must be 18cm between holes). So far that’s the best solution I found out regarding ease of maintenance, performance and cost.

The Bosch S4 001 weights 10kg. That’s an extra 4kg but they worth it !

To remove the battery you need to remove the black metal plate and the rear strut brace. Easy job but a lot for a single battery change.

The original and the Bosch batteries :

The Bosch S4001 fits easily but you will need to trim the rear bottom of it because of the strut brace :

The Bosch S4 001 installed with the terminal adapters. Needless to say the car starts easier than with the original battery !